Electrosurgical methods and apparatus for making precise incisions in body vessels

ABSTRACT

Methods and apparatus employed in surgery involving making precise incisions in vessels of the body, particularly cardiac blood vessels in coronary revascularization procedures conducted on the stopped or beating heart are disclosed. Such incisions are created by applying an elongated electrosurgical cutting electrode to the outer surface of the vessel wall in substantially parallel alignment with the body vessel axis, the elongated electrosurgical cutting electrode having a predetermined cutting electrode length exceeding the cutting electrode width. RF energy is applied between the electrosurgical cutting electrode and the ground electrode at an energy level and for a duration sufficient to cut an elongated slit through the vessel wall where the elongated electrosurgical cutting electrode is applied to the surface of the vessel wall.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.10/917,755, filed Aug. 13, 2004, now U.S. Pat. No. 7,189,231, which is adivisional of U.S. application Ser. No. 10/278,966, filed Oct. 23, 2002,now U.S. Pat. No. 6,960,209.

FIELD OF THE INVENTION

The present invention pertains to methods and apparatus employed insurgery involving making precise incisions in vessels of the body,particularly cardiac blood vessels in coronary revascularizationprocedures conducted on the stopped or beating heart.

BACKGROUND OF THE INVENTION

Diseases of the cardiovascular system affect millions of people eachyear and are a leading cause of death throughout the world. The cost tosociety from such diseases is enormous both in terms of the number oflives lost as well as in terms of the costs associated with treatingpatients through traditional surgical techniques. A particularlyprevalent form of cardiovascular disease is caused by atherosclerosis, aform of arteriosclerosis.

Atherosclerosis is a disease in which the lumen (interior passage) of anartery becomes stenosed (narrowed) or even totally occluded (blocked) byan accumulation of fibrous, fatty, or calcified tissue. Over time thistissue, known in medicine as an atheroma, hardens and occludes theartery. The partial stenosis or full occlusion of the coronary arteriesthat supply the heart muscle leads to ischemia (deficient blood flow) ofthe heart muscle, angina (chest pain), and can lead to infarction (heartattack) or patient death. Although drug therapies and modifications todiet and lifestyle show great promise for preventing and treatingatherosclerotic vascular disease, many patients urgently requirerestoration of blood flow that has already been lost, especially inthose having severely or totally occluded blood vessels.

In many cases, a patient suffering a coronary vessel obstruction orrestriction undergoes a coronary artery bypass graft (CABG) surgicalprocedure, more commonly known as a “heart bypass” operation to restorenormal oxygenated blood flow to the heart muscle downstream of theobstruction or restriction. More particularly, a fluid connection or“distal anastomosis.” is surgically established between a source vesselof oxygenated blood and the obstructed or restricted target coronaryartery downstream or distal to the obstruction or restriction to restorethe flow of oxygenated blood to the heart muscle. In one approach, thesurgeon attaches an available source vessel, e.g., an internal mammaryartery (IMA), directly to the obstructed target coronary artery at thedistal anastomosis site downstream from the obstruction or restriction.

There are a number of alternative approaches to CABG surgery. In oneapproach, the surgeon harvests a graft blood vessel from the patient'svenous system and prepares its proximal and distal ends to be attachedin a “proximal anastomosis” and a “distal anastomosis” bypassing theocclusion. This type of graft is commonly known as a “free” graft. Theproximal anastomosis can be located proximal or upstream to theocclusion or to another vessel supplying oxygenated blood, e.g., theaorta. Typically, a section of the saphenous vein is harvested from thepatient's body. Sometimes, the internal mammary artery (IMA) is used asthe graft blood vessel or the radial artery is used as arterial conduitand the proximal anastomosis has to be made. In another approach,artery-to-artery bypass procedures have been utilized in which anarterial source of oxygenated blood, e.g., the left IMA or right IMA, issevered and a portion is dissected away from supporting tissue so thatthe severed end can be anastomosed to the obstructed coronary arterydistally to the stenosis or occlusion. More recently, other arterieshave been used in such procedures, including the inferior epigastricarteries and gastroepiploic arteries. It is also stated in U.S. Pat. No.6,080,175 that a conventional electrosurgical instrument can beintroduced through a port or incision and used to dissect and preparethe bypass graft vessel for coronary anastomosis while viewing theprocedure through a thoracoscope.

It is necessary to access and prepare the site or sites of the vesselwall of the target coronary artery where the proximal and/or distalanastomosis is to be completed and to then make the surgical attachmentsof the blood vessels. First, it is necessary to isolate the anastomosissite of the target coronary artery from the epicardial tissues andoverlying fatty layers. Typically, blunt, rounded #15 scalpel blades areemployed to dissect these tissues and layers away from the targetcoronary artery.

Generally, blood flow in the target coronary artery is interrupted by,for example, temporary ligation or clamping of the artery proximal anddistal of the anastomosis site, and the target coronary artery wall isopened to form an arteriotomy, that is, an elongated incision at theanastomosis site extending parallel to the axis of the coronary vesseland equally spaced from the sides of the coronary artery that are stillembedded in or against the epicardium. The arteriotomy is typicallycreated by use of a very sharp, pointed, #11 scalpel blade to perforatethe coronary artery wall, and the puncture is elongated the requisitelength using scissors. A “perfect arteriotomy” is an incision that hasstraight edges, that does not stray from the axial alignment and equaldistance from the sides of the coronary artery, and is of the requisitelength.

Similarly, it is necessary to prepare the attachment end of the sourcevessel by cutting the source vessel end at an appropriate angle for anend-to-side or end-to-end anastomosis or by forming an elongatedarteriotomy in the source vessel wall of a suitable length that isaxially aligned with the source vessel axis for a side-to-sideanastomosis. Typically, the surgeon uses surgical scalpels and scissorsto shape the source vessel end or make the elongated arteriotomy slit inthe source vessel, and uses sutures or clips to close the open severedend.

In the example depicted schematically in FIG. 1, the heart 12 isprepared as described above for an end-to-side anastomosis of thesurgically freed, severed, and appropriately shaped vessel end 31 of theleft IMA 30 branching from the aorta 16 and left subclavian artery 18 tothe prepared arteriotomy 15 in the vessel wall of the left anteriordescending (LAD) coronary artery 14 downstream from the obstruction 38.Similarly, in the example depicted schematically in FIG. 3, the heart 12is prepared as described above for a side-to-side anastomosis of theleft IMA 30 to the prepared arteriotomy 15 in the vessel wall of the LADcoronary artery 14. In the side-to-side anastomosis, an arteriotomy 33is made in the freed segment of the left IMA 30, and the vessel end 31is sutured closed.

The prepared end or elongated arteriotomy of the bypass graft or sourcevessel is attached or anastomosed to the target coronary artery at thearteriotomy in a manner that prevents leakage of blood employingsutures, staples, surgical adhesives and/or various artificialanastomosis devices. For example, an end-to-side anastomosis 35 of theshaped vessel end 31 of the left IMA 30 to the prepared arteriotomy 15in the vessel wall of the LAD coronary artery 14 is illustrated in FIG.2. And a side-to-side anastomosis 37 joining the arteriotomy 33 of theleft IMA 30 to the prepared arteriotomy 15 of the LAD coronary artery 14is illustrated, for example, in FIG. 4.

The inner, endothelial layer, vessel linings are less thrombogenic thanthe outer epithelial layers of blood vessels. So, in one approach, theattachment is made by everting and applying the interior linings of thebypass graft or source vessel and the target coronary artery against oneanother and suturing or gluing or otherwise attaching the interiorlinings together. Various types of artificial biocompatiblereinforcement sleeves or rings, e.g., those shown in theabove-referenced '369 patent can also be used in the anastomosis.Currently, a number of mechanical anastomotic devices, materials,techniques, and procedures are being developed for facilitating theprocess of forming an anastomosis including vascular clips or staplers,glues, adhesives or sealants, laser welding, mechanical couplers, stentsand robot-assisted suturing. These techniques are being developed forperforming end-to-end, end-to-side and/or side-to-side anastomoses withor without temporary blood flow interruption. In general, thesetechniques can include the use of various biomaterials and/orbiocompatible agents. See, for example, U.S. Pat. Nos. 5,385,606,5,695,504, 5,707,380, 5,972,017 and 5,976,178, and 6,231,565.

Various examples of forming the target vessel arteriotomy orarteriotomies, the shaped end or side wall arteriotomy of the sourcevessel, and the positioning and attachment of the source vessel andtarget artery together are set forth in U.S. Pat. Nos. 5,776,154,5,799,661, 5,868,770, 5,893,369, 6,026,814, 6,071,295, 6,080,175,6,248,117, 6,331,158, and 6,332,468.

In a conventional bypass graft or CABG procedure, the surgeon exposesthe obstructed coronary vessel through an open chest surgical exposureor thoracotomy providing direct visualization and access to theepicardium. Typically, fat layers that make it difficult to see eitherthe artery or the occlusion cover the epicardial surface and theobstructed cardiac artery. However, surgeons are able to dissect the fataway to expose the artery and manually palpate the heart to feel therelatively stiff or rigid occlusion within the artery as a result oftheir training and experience. The surgeon can determine the locationand length of the occlusion as well as suitable sites of the targetcoronary artery for the proximal and distal anastomoses with some degreeof success.

The open chest procedure involves making a 20 to 25 cm incision in thechest of the patient, severing the sternum and cutting and peeling backvarious layers of tissue in order to give access to the heart andarterial sources. As a result, these operations typically require largenumbers of sutures or staples to close the incision and 5 to 10 wirehooks to keep the severed sternum together. Such surgery often carriesadditional complications such as instability of the sternum,post-operative bleeding, and mediastinal infection. The thoracic muscleand ribs are also severely traumatized, and the healing process resultsin an unattractive scar. Post-operatively, most patients enduresignificant pain and must forego work or strenuous activity for a longrecovery period.

Many minimally invasive surgical techniques and devices have beenintroduced. In order to reduce the risk of morbidity, expense, trauma,patient mortality, infection, and other complications associated withopen chest cardiac surgery. Less traumatic limited open chest techniquesusing an abdominal (sub-xyphoid) approach or, alternatively, a“Chamberlain” incision (an approximately 8 cm incision at thesternocostal junction), have been developed to lessen the operating areaand the associated complications. In recent years, a growing number ofsurgeons have begun performing CABG procedures performed while the heartis still beating using minimally invasive direct coronary artery bypassgrafting (MIDCAB) surgical techniques and devices. Using the MIDCABmethod, the heart typically is accessed through a mini-thoracotomy(i.e., a 6 to 8 cm incision in the patient's chest) that avoids thesternal splitting incision of conventional cardiac surgery. A MIDCABtechnique for performing a CABG procedure is described in U.S. Pat. No.5,875,782, for example.

Other minimally invasive, percutaneous, coronary surgical procedureshave been advanced that employ multiple small trans-thoracic incisionsto and through the pericardium, instruments advanced through sleeves orports inserted in the incisions, and a thoracoscope to view the accessedcardiac site while the procedure is performed as shown, for example, inthe above-referenced '175, '295, '468 and '661 patents and in U.S. Pat.Nos. 5,464,447, and 5,716,392. Surgical trocars having a diameter ofabout 3 mm to 15 mm are fitted into lumens of tubular trocar sleeves orports, and the assemblies are inserted into skin incisions. The trocartip is advanced to puncture the abdomen or chest to reach thepericardium, and the trocar is then withdrawn leaving the port in place.Surgical instruments and other devices such as fiber optic thoracoscopescan be inserted into the body cavity through the port lumens. As statedin the '468 patent, instruments advanced through trocars can includeelectrosurgical tools, graspers, forceps, scalpels, electrocauterydevices, clip appliers, scissors, etc.

In the above-described procedures, the surgeon can stop the heart byutilizing a series of internal catheters to stop blood flow through theaorta and to administer cardioplegia solution. The endoscopic approachutilizes groin cannulation to establish cardiopulmonary bypass (CPB) andan intraaortic balloon catheter that functions as an internal aorticclamp by means of an expandable balloon at its distal end used toocclude blood flow in the ascending aorta. A full description of anexample of one preferred endoscopic technique is found in U.S. Pat. No.5,452,733, for example.

However, recently developed, beating heart procedures eliminate the needfor any form of CPB, the extensive surgical procedures necessary toconnect the patient to a CPB machine, and to stop the heart. A number ofsurgical instruments have been developed that attempt to stabilize orimmobilize a portion of the beating heart that supports the targetcoronary artery and the anastomosis site. These beating heart proceduresdescribed, for example, in the above-referenced '158, '175, '770, '782,and '295 patents and in U.S. Pat. Nos. 5,976,069, and 6,120,436, can beperformed on a heart exposed in a full or limited thoracotomy oraccessed percutaneously.

For example, a retractor assembly disclosed in the above-referenced '158patent mounts to and maintains the chest opening while supporting astabilizer assembly that extends parallel stabilizer bars against theepicardium alongside the target coronary artery so that force is appliedacross the anastomosis site to suppress heart motion. The surgeonemploys conventional manually applied clamps to block blood flow throughthe arterial lumen and scalpels and scissors to make the elongatedincision of the arteriotomy.

Instruments are disclosed in the above-referenced '295 patent that applysuction to the epicardial surface around or alongside the anastomosissite to suppress heart motion. Again, the surgeon employs theconventional manually applied clamps to block blood flow through thearterial lumen and a scalpel to make the elongated incision of thearteriotomy.

Instruments that combine the application of suction to the epicardialsurface around or alongside the anastomosis site to suppress heartmotion with a cutting mechanism for making the arteriotomy are disclosedin the above-referenced '175 and '770 patents. The surgical cuttinginstruments disclosed in the '770 and '175 patents include an elongatedshaft having a proximal end, a distal end adapted for percutaneousinsertion against the target coronary artery over the anastomosis site,and an axial lumen therebetween. A suction pad is formed at the distalend of the shaft, and a cutting element disposed within the lumen of theshaft near the distal end. A vacuum line is fluidly coupled to the lumenof the shaft and is adapted to connect to a vacuum source to effect asuction force at the distal end of the shaft. A control mechanism isprovided to selectively block flow between the vacuum source and thelumen. The control mechanism may include a slide valve, an on/offbutton, or other equivalent mechanism for selectively closing andopening the vacuum pathway. A gripper assembly configured to grip aportion of the coronary artery is also disclosed in the '175 patent.

The cutting element and the shaft are relatively moveable between aretracted position and a cutting position. The cutting element isadapted to make the elongated slit of the arteriotomy in alignment withthe axis of the coronary artery when the cutting element and the shaftare in the cutting position and the vacuum holds the anastomosis sitesteady.

The distal end of the shaft disclosed in the '175 patent has an outsidediameter of less than about 5 mm, and the cutting element comprises atleast one cutting element having a substantially straight blade cuttingedge. The cutting edge is displaced at an angle of between about 15 to30 degrees relative to a vertical axis through the cutting element. Inone embodiment, the cutting element is fixed to an actuator push rodlocated within the lumen of the shaft, and connected to an actuator,preferably an actuator button, at a proximal end thereof. In anotherembodiment, the shaft is slidably mounted to a handle of the cuttinginstrument. An anchor, preferably a rigid rod coaxially disposed withinthe shaft, fixes the cutting element to the handle. An actuator membermounted to the shaft and biased by a spring is actuated to slide theshaft between retracted and cutting positions with respect to thecutting element.

Additionally or alternatively, at least one electrode may be disposednear the distal end of the shaft to effect or enhance cutting. Theelectrode may be operatively coupled to the cutting element, preferablysubstantially co-linearly coupled to the cutting edge. In the depictedembodiments, the electrode extends to the sharpened tip of the cuttingelement opposite to the cutting blade. In use, the end of the electrodeat the tip of the cutting element is placed against the coronary arteryand energized by radio frequency energy as the cutting element is movedto the cutting position to facilitate making a small point incision orpilot hole in the coronary artery. Then, the cutting blade is fullyadvanced to make the elongated cut. Ultrasonic energy may be applied tothe cutting element to effect or enhance cutting by the ultrasonicallyvibrating the cutting blade.

All of the above-described approaches employ a cutting blade to make theelongated slit of the arteriotomy. In most cases, the shaft must becarefully moved to advance the cutting blade along the length of thevessel wall without inadvertently pushing the tip of blade across thevessel lumen and through the vessel wall opposite to the intended slit.Damage can be caused to the vessel wall if care is not taken.

A vessel wall cutting instrument or tool is needed for making anarteriotomy or a similar slit in a vessel wall is needed that avoids orminimizes the need to move the cutting tool or the cutting blade alongthe vessel wall to slit the vessel wall to a desired length.

A vessel wall cutting instrument or tool is needed that does notinadvertently advance across the vessel wall from the slit and damagethe vessel wall opposite to the slit.

A vessel wall cutting instrument or tool is needed that enablesocclusion of the blood vessel to inhibit blood loss through the incisionas the incision is being made.

A vessel wall cutting instrument is also needed that can make a cleanstraight incision of predetermined length and width in a vessel wallquickly within the time between heart contractions.

SUMMARY OF THE INVENTION

The present invention is preferably embodied in electrosurgical methodsand apparatus for making precise elongated incisions or slits extendinglengthwise along and through a vessel wall, e.g., arteriotomy incisionsor slits in coronary arteries and source vessels.

In accordance with one aspect of the present invention a method andapparatus for performing the method of making an elongated slit throughthe vessel wall and into the lumen of a body vessel, having a bodyvessel axis, of a patient comprises accessing the outer surface of thevessel wall, applying a ground electrode in contact with the body of thepatient, applying an elongated electrosurgical cutting electrode to theouter surface of the vessel wall in substantially parallel alignmentwith the body vessel axis, the elongated electrosurgical cuttingelectrode having a predetermined cutting electrode length exceeding thecutting electrode width, and applying RF energy between theelectrosurgical cutting electrode and the ground electrode at an energylevel and for a duration sufficient to cut an elongated slit through thevessel wall where the elongated electrosurgical cutting electrode isapplied to the outer surface of the vessel wall.

The present invention advantageously provides plurality of unipolar andbipolar electrosurgical vessel wall cutting instruments or tools formaking an arteriotomy or a similar slit in a vessel wall that avoid orminimize the need to move the cutting blade either along the vessel wallto slit the vessel wall to a desired length and that do notinadvertently advance across the vessel wall from the slit and damagethe vessel wall opposite to the slit.

This summary of the invention has been presented here simply to pointout some of the ways that the invention overcomes difficulties presentedin the prior art and to distinguish the invention from the prior art andis not intended to operate in any manner as a limitation on theinterpretation of claims that are presented initially in the patentapplication and that are ultimately granted.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other advantages and features of the present invention will bemore readily understood from the following detailed description of thepreferred embodiments thereof, when considered in conjunction with thedrawings, in which like reference numerals indicate identical structuresthroughout the several views, and wherein:

FIG. 1 is a schematic illustration of the preparation of a source vesselfree end and an arteriotomy in a coronary artery downstream from anobstruction for an end-to-side anastomosis;

FIG. 2 is a schematic illustration of the end-to-side anastomosis of thesource vessel free end to the arteriotomy in the coronary artery;

FIG. 3 is a schematic illustration of the preparation of a source vesselfree end and an arteriotomy in a coronary artery downstream from anobstruction for a side-to-side anastomosis;

FIG. 4 is a schematic illustration of the side-to-side anastomosis ofthe arteriotomy in the source vessel to the arteriotomy in the coronaryartery;

FIG. 5 is an illustration of the preparation of a patient for apercutaneous CABG procedure and particularly the determination of asuitable anastomosis site in a coronary artery;

FIG. 6 is a schematic illustration of the application of anelectrosurgical cutting electrode to the exterior vessel wall of acoronary artery and a ground electrode within the arterial lumen to forman arteriotomy in the vessel wall;

FIG. 7 is a side view of a first preferred embodiment of a unipolarelectrosurgical vessel wall cutting tool of the present invention;

FIG. 8 is an expanded end view in partial cross-section of the distalportion of the unipolar electrosurgical vessel wall cutting tool of FIG.7;

FIG. 9 is an expanded side view of the distal portion of the unipolarelectrosurgical vessel wall cutting tool of FIG. 7;

FIG. 10 is a schematic illustration of the application of theelectrosurgical instrument cutting electrode of the unipolarelectrosurgical vessel wall cutting tool of FIG. 7 to the exteriorvessel wall of a coronary artery and a ground electrode within thearterial lumen to form an arteriotomy in the vessel wall;

FIG. 11 is a side view of a first preferred embodiment of a bipolarelectrosurgical vessel wall cutting tool of the present invention;

FIG. 12 is an expanded end view of the distal portion of the bipolarelectrosurgical vessel wall cutting tool of FIG. 11;

FIG. 13 is a side view of a first preferred embodiment of a bipolarelectrosurgical vessel wall cutting tool of the present invention;

FIG. 14 is an expanded end view of the distal portion of the bipolarelectrosurgical vessel wall cutting tool of FIG. 13;

FIG. 15 is an expanded side view of the distal portion of the bipolarelectrosurgical vessel wall cutting tool of FIG. 13;

FIG. 16 is an expanded side view of a first variant of the distalportion of the bipolar electrosurgical vessel wall cutting tool of FIG.13;

FIG. 17 is an expanded side view of a second variant of the distalportion of the bipolar electrosurgical vessel wall cutting tool of FIG.13;

FIG. 18 is a schematic illustration of the application of theelectrosurgical instrument wire cutting and ground electrodes of afurther embodiment of a bipolar electrosurgical vessel wall cutting toolon either side of the vessel wall of a coronary artery to create anarteriotomy;

FIG. 19 is an expanded side view of a first variant of the distalportion of the bipolar electrosurgical vessel wall cutting tool of FIG.18;

FIG. 20 is an expanded side view of a second variant of the distalportion of the bipolar electrosurgical vessel wall cutting tool of FIG.18;

FIG. 21 is a schematic illustration of the application of theelectrosurgical instrument wire cutting and ground electrodes of a stillfurther embodiment of a bipolar electrosurgical vessel wall cutting toolto the outer surface of the vessel wall of a coronary artery to createan arteriotomy;

FIG. 22 is an expanded side view of the distal portion of the bipolarelectrosurgical vessel wall cutting tool of FIG. 21 with the wirecutting and ground electrodes separated apart in a non-operativeconfiguration;

FIG. 23 is an expanded side view of the distal portion of the bipolarelectrosurgical vessel wall cutting tool of FIG. 21 with the wirecutting and ground electrodes drawn together engaging a portion of thevessel wall to create an arteriotomy;

FIG. 24 is a schematic illustration of the application of a furtherembodiment of an electrosurgical vessel wall cutting tool of theinvention applied to the outer surface of the wall of a coronary arteryto create an arteriotomy as an area of the beating heart is immobilizedby suction;

FIG. 25 is a schematic illustration of the application of a furtherembodiment of an electrosurgical vessel wall cutting tool of theinvention applied to the outer surface of the wall of a coronary arteryto create an arteriotomy as an area of the beating heart is immobilizedby pads extending from the electrosurgical vessel wall cutting toolalongside the artery;

FIG. 26 is a schematic illustration of the application of a furtherembodiment of an electrosurgical vessel wall cutting tool of theinvention applied to the outer surface of the wall of a coronary arteryto create an arteriotomy as an area of the beating heart is immobilizedby suction pads extending from the electrosurgical vessel wall cuttingtool alongside the artery;

FIG. 27 is a schematic illustration of the application of a furtherembodiment of an electrosurgical vessel wall cutting tool of theinvention applied to the outer surface of the wall of a coronary arteryto create an arteriotomy as an area of the beating heart is immobilizedand the vessel occluded by a frame extending from the electrosurgicalvessel wall cutting tool alongside the artery;

FIG. 28 is a schematic illustration of the application of a furtherembodiment of an electrosurgical vessel wall cutting tool of theinvention applied to the outer surface of the wall of a coronary arteryto create an arteriotomy as an area of the beating heart is immobilizedby suction applied to the artery as RF energy is applied;

FIG. 29 is an end view of the electrode head of the electrosurgicalvessel wall cutting tool of FIG. 28;

FIG. 30 is partial side view of the electrode head of theelectrosurgical vessel wall cutting tool of FIG. 28 applied against avessel wall;

FIG. 31 is an end view of a variation of the electrode head of theelectrosurgical vessel wall cutting tool of FIG. 28;

FIG. 32 is partial side view of the electrode head of theelectrosurgical vessel wall cutting tool of FIG. 31;

FIG. 33 is a schematic illustration of the application of a furtherembodiment of an electrosurgical vessel wall cutting tool of theinvention applied to the outer surface of the wall of a coronary arteryand a wire ground electrode introduced into the vessel lumen through aneedle puncture of the vessel wall to create an arteriotomy as RF energyis applied;

FIG. 34 is an enlarged detail view of the electrosurgical vessel wallcutting tool of FIG. 33 illustrating introduction of the ground wireinto or retraction of the ground wire from the vessel lumen;

FIG. 35 is an enlarged detail view of the electrosurgical vessel wallcutting tool of FIG. 33 illustrating full introduction of the groundwire within the vessel lumen;

FIG. 36 is a partial cross-section view of the distal portion of avariation of the electrode head of the electrosurgical vessel wallcutting tools of the present invention incorporating a pressureresponsive switch with the switch pads open;

FIG. 37 is a partial cross-section view of the distal portion of avariation of the electrode head of the electrosurgical vessel wallcutting tools of the present invention incorporating a pressureresponsive switch with the switch pads closed;

FIG. 38 is a schematic illustration of the application of theelectrosurgical vessel wall cutting tool of FIG. 28 applied to the sidewall of a source vessel to create an arteriotomy for a side-to-sideanastomosis with a coronary artery;

FIG. 39 is a schematic illustration of a further embodiment of anelectrosurgical vessel wall cutting tool for forming an elongated slitin a source vessel to create an arteriotomy for a side-to-sideanastomosis with a coronary artery;

FIG. 40 is a schematic illustration of a still further embodiment of anelectrosurgical vessel wall cutting tool for forming an elongated slitin a source vessel to create an arteriotomy for a side-to-sideanastomosis with a coronary artery;

FIG. 41 is an enlarged detail view of the electrosurgical cuttingelectrode of the electrosurgical vessel wall cutting tool of FIG. 40;

FIG. 42 is an enlarged detail view of the ground electrode of theelectrosurgical vessel wall cutting tool of FIG. 40;

FIG. 43 is a further embodiment of an electrosurgical vessel wallcutting tool having sensing electrodes for forming an elongated slit ina source vessel to create an arteriotomy;

FIG. 44 is another view of the electrosurgical vessel wall cutting toolof FIG. 43;

FIG. 45 is an end view of a portion of the electrosurgical vessel wallcutting tool of FIG. 43; and

FIG. 46 is a side view of a portion of the electrosurgical vessel wallcutting tool of FIG. 43.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following detailed description, references are made toillustrative embodiments for carrying out the invention. It isunderstood that other embodiments may be utilized without departing fromthe scope of the invention.

For example, while a preferred method of forming arteriotomies in acoronary artery and a source vessel in the process of performing acoronary artery anastomosis in a thoracoscopic CABG procedure will bedescribed herein, it is to be understood that the principles of thepresent invention may be applied to a wide variety of surgicalprocedures, both conventional, open chest procedures, as well asminimally invasive, closed chest procedures, to form precise elongatedslits in vessel walls.

Electrosurgical instruments of the present invention are employed toefficiently form “perfect arteriotomies” in vessel walls through thepassage of a radio frequency current between an active, linear, cuttingelectrode applied to the vessel wall in alignment with the vessel axisand a ground pad contacting the patient's skin or a ground electrodeintroduced transluminally into the vessel lumen. The RF current cutstissue at the active cutting electrode, the cutting rate being dependanton current density through the tissue contacted by the active cuttingelectrode. Rapid, clean edge slits are made through the vessel wall whencurrent density exceeds a threshold that causes the fluid within thecells to turn to steam, creating a sufficient overpressure so as toburst the cell walls. The cells then dry up, desiccate, and carbonize,resulting in localized shrinking and an opening in the tissue.

Current density depends upon the area the active cutting electrodepresents to the vessel wall, the series impedance, typically resistance,to current flow between the active and ground pad or ground electrode,and the voltage applied to the series impedance. Current density isinversely proportional to active electrode contact area, so currentdensity increases as active electrode surface area decreases. Thecurrent density is typically adjusted by varying the voltage applied tothe active electrode since the area of a particular electrosurgicalinstrument active electrode is fixed and the series impedance cannotalways be controlled.

The series impedance is dependent upon several factors including thematerial and design of the active cutting electrode, the type, thicknessand conductivity of tissue and fluid between the active cuttingelectrode and the ground pad or electrode, the intimacy of contact ofthe cutting electrode with the tissue to be cut, and the location of thegrounding pad or electrode relative to the cutting electrode. RF energygenerators used in this type of surgery have a wide range of poweroutput to accommodate a variety of procedures and devices. For example,the RF energy generator can be adjusted to either cut tissue or tomerely cauterize previously cut or torn tissue.

The objective in electrosurgical tissue cutting is to heat the cells ofthe tissue so rapidly that they explode into steam leaving a cavity inthe cell matrix. The heat is meant to be dissipated in the steam and notto dry out adjacent cells. When the electrode is moved and fresh tissueis contacted, new cells are exploded, and the incision is made orcontinued. The electrical current utilized in electrosurgical cutting isin the radio frequency range and operates by jumping across an air gapto the tissue. This is commonly referred to as sparking. An explanationof electrosurgical cutting theory can be found in the FORCE 1Instruction Manual published by Valleylab, Inc. of Boulder, Colo., anddated Mar. 1, 1986.

In accordance with the present invention, electrosurgical cuttinginstruments and associated instruments and methods are provided that canbe used in any of the above described full exposure surgical proceduresor less invasive MIDCAB or percutaneous exposures of the vessels inquestion, particularly, the above-described CABG procedures on a stoppedor beating heart.

Exemplary Percutaneous Surgical Exposure:

Thus, for example, FIG. 5 depicts the preparation of the patient 10 fora CABG procedure performed percutaneously and advantageously while theheart 12 is beating. Percutaneous access to the blocked coronary arteryand source vessel as well as intra-arterial access into the arteriallumens to effect an artery-to-artery. CABG procedure are depicted inFIG. 5. Electrosurgical instruments and methods of the present inventionare employed to make the arteriotomy 15 in the side-wall of the LADcoronary artery 14 distal to the site of an obstruction 38 for either ofthe end-to-side vascular anastomosis as depicted, for example, in FIGS.1 and 2 or the side-to-side vascular anastomosis as depicted, forexample, in FIGS. 3 and 4 and, in the latter procedure, the arteriotomy33 in the side wall of the freed end portion of the left IMA 30.

It will be understood that an angiography of the coronary arteries ofthe heart of the patient 10 has been completed to identify theobstruction 38 in the LAD coronary artery 14. Typically, the surgeonwill already have an angiogram of the affected coronary artery availableas a result of the earlier diagnosis of the necessity for the coronarybypass.

The patient 10 is placed under general anesthesia, and the patient'sleft lung is deflated using conventional techniques. The patient 10 isplaced in a lateral decubitus position on his right side, and multiplesmall percutaneous incisions are to be made in the chest wall for thereceipt of surgical instruments. As used herein, the term “percutaneous”refers to any penetration through the skin of the patient, whether inthe form of a small cut, incision, hole, cannula, trocar sleeve or portor the like. For example, two small incisions are made in the chest wallof patient 10 at different interstitial positions between the patient'sribs, while a third incision is made just below the sternum.

First, the surgeon identifies a suitable position for insertion of aBeress insufflation needle or other suitable needle based upon thepathology and anatomy of the patient 10. Typically, this needle will beinserted between the fifth or sixth intercostal space along the anterioraxillary line and into the region between the parietal pleura and thepericardium. The parietal pleura and pericardium are then separated, andthe Beress needle is removed.

A first trocar (not shown) having a sharpened tip is inserted in thelumen of port 32 having a diameter of approximately 8 to 12 mm and,preferably, 10 mm, and the assembly is then inserted into the thoraciccavity along the same path traveled by the Beress insufflation needle.The trocar is then removed from port 32 and a conventional endoscopictelescope or thoracoscope (not shown) is introduced through the port 32into the thoracic cavity. This thoracoscope is used to directlyvisualize the thoracic cavity and obtain a left lateral view of thepericardial sac or pericardium over the heart 12.

The surgeon determines the best locations for insertion of the assemblyof a second trocar (not shown) and port 34 and the assembly of a thirdtrocar (not shown) and port 36 based upon direct visualization throughthe thoracoscope of the pericardium overlying the heart 12, the presumedlocations of the coronary artery of interest and the source artery aswell as the anatomy and pathology of the patient 10 may be determinedthrough biplane fluoroscopy and an angiogram. Typically, the secondtrocar and port 34 is inserted through the intercostal wall and into thethoracic cavity, and the third trocar and port 36 is inserted throughthe subxyphoid space. Additional trocars or other instruments can beinserted percutaneously as necessary. Often, it will be advantageous toinsert a fourth trocar and port for introducing a clipping or suturingdevice into the thoracic cavity. In each case, the trocars are removedleaving the ports in place.

The parietal pleura is dissected and the pericardial sac is opened byinstruments introduced through the second port 34 and/or the third port36 using conventional techniques while visualizing the site through thethoracoscope. The thoracoscope is used to view the LAD coronary artery14, in this case, to the extent that it can be seen because of overlyingfatty tissue, and the location of the source artery, left IMA 30 in thiscase.

At this juncture, the LAD coronary artery 14 is identified, the locationof the occlusion 38 is ascertained, and fatty tissue is dissected awayat the proximal and/or distal sites of anastomosis. A distal portion ofthe left IMA 30 is dissected and freed from tissue as described above.The left IMA distal end 31 is shaped in preparation for the end-to-sideanastomosis or the arteriotomy 33 of FIGS. 3 and 4 is performedemploying the electrosurgical instruments and methods described indetail herein in preparation for the side-to-side anastomosis.

Electrosurgical Arteriotomy Instruments and Techniques:

In this example of the practice of the present invention, anelectrosurgical arteriotomy instrument or tool 60 of one of the typesdescribed further herein is inserted through one of the ports 34 or 36and the opening in the pericardial sac as shown schematically in FIG. 6.The arteriotomy tool distal cutting head 62, having at least oneelongated electrosurgical cutting electrode, is directed against theepicardium under visualization employing the thoracoscope extendingthrough port 32. The beating heart 12 is stabilized or stilled in thearea surrounding or beside site of the arteriotomy 15 employing one ormore of the techniques and devices as described further herein. The axisof the elongated electrosurgical cutting electrode(s) is centered overthe exposed arterial vessel wall and aligned to the axis of LAD coronaryartery 14 at the arteriotomy site downstream from the obstruction 38. Inbipolar embodiments of the arteriotomy tool 60, the return or groundelectrode(s) is supported at the arteriotomy tool distal cutting head62. In unipolar embodiments of the arteriotomy tool 60, a return orground pad can be applied to the patient's skin. Alternatively, a returnor ground electrode is introduced into the lumen of the LAD coronaryartery 14 into close proximity with the cutting electrode at thearteriotomy tool distal cutting head 62. RF energy is then appliedthrough the elongated electrosurgical cutting electrode(s) and thereturn or ground electrode.

Thus, in certain embodiments of the present invention, the catheter body44 of a femoral catheter 40 is introduced into the femoral artery 24 andadvanced into the aorta 16 to locate the femoral catheter distal end 42at or within the ostium of the LAD coronary artery 14 as shown in FIGS.5 and 6. An elongated arterial ground wire 50 having a distal groundelectrode 52 at or adjacent to the elongated ground wire distal end ofthe electrically insulated wire body 54 is advanced through the catheterlumen and out of the catheter lumen distal end opening into the lumen 48of LAD coronary artery 14. The distal ground electrode 52 is thenadvanced, if possible, through the occlusion 38 to position the distalground electrode 52 downstream from the occlusion 38 by rotation andback and forth manipulation of the ground wire proximal end 58 exitingthe femoral catheter 40 outside the patient's body. A radiopaque ring orthe like is carried on the ground wire body 54 at or somewhat proximalto the distal ground electrode 52 so that advancement of the distalground electrode 52 from the catheter lumen end opening and within thearterial lumen 48 of the LAD coronary artery 14 can be monitored viafluoroscopy.

The progress of the distal ground electrode 52 as it is advanced throughor is blocked by the occlusion 38 can also be ascertained employing theelectrosurgical tool 60 that is advanced through one of the ports 34 and36 as a location determining probe. The arteriotomy tool distal cuttinghead 62 is applied against the epicardium over the suspected location ofthe LAD coronary artery 14 while the arteriotomy tool distal cuttinghead 62 and the epicardial surface are observed through the thoracoscopeinserted through port 32. The arteriotomy tool distal cutting head 62 ismoved about against the epicardium over the suspected location of theLAD coronary artery 14 while low energy electrical current flows throughthe series impedance between the cutting electrode at the arteriotomytool distal cutting head 62 and the ground electrode 52. The impedancebetween the cutting electrode at the arteriotomy tool distal cuttinghead 62 and the ground electrode 52 can be measured to determine whenthe cutting electrode at the arteriotomy tool distal cutting head 62 isclosest to the ground electrode 52.

The RF energy is applied between the cutting electrode at thearteriotomy tool distal cutting head 62 and the ground electrode 52within arterial lumen 48 to cut through the wall of the LAD coronaryartery 14 after it is determined that the relative locations of thecutting electrode at the arteriotomy tool distal cutting head 62 and theground electrode 52 are optimized. The elongated electrosurgical cuttingelectrode is aligned with the axis of and centered over the exposedexterior wall of LAD coronary artery 14, and the applied energy heatsand explodes the tissue cells contacted by the elongated cutting elementthereby cutting a narrow, straight, clean slit through the arterialwall. The length, width and shape of the slit depends upon thecorresponding length, width and shape of the active cutting element atthe arteriotomy tool distal cutting head 62.

The impedance of the series circuit between the elongatedelectrosurgical cutting electrode at the arteriotomy tool distal cuttinghead 62 and the ground electrode 52 can be monitored during applicationof the RF energy. The sudden lowered impedance characteristic of passageof the elongated electrosurgical cutting electrode through the vesselwall can be detected and employed to signal completion and/or toautomatically terminate the RF energy. The RF energy is automaticallycut-off if the cutting electrode at the arteriotomy tool distal cuttinghead 62 and the ground electrode 52 come into contact.

Overheating of adjacent tissue with accompanying desiccation and damageis advantageously limited or prevented through the particular designs ofthe electrosurgical cutting instruments or tools 60 of the presentinvention. Thus, this procedure provides a clean cut at arteriotomy 15without damage to adjacent tissue. A clean, controlled cut of aprescribed length in axial alignment with the vessel axis and isparticularly desirable to assure that tearing does not occur in adirection away from the desired orientation of the cut.

It will be understood that this procedure of forming the arteriotomy 15can be conducted while the patient's heart 12 is beating or is stoppedin the conventional manner. In the former case, miniaturized instrumentsdescribed herein can be advanced through one of the ports 32, 34, 36into operative relation with heart 12 for stabilizing a region of thebeating heart about the site of the arteriotomy 15 to facilitate itsformation and the anastomosis with the source vessel.

A number of electrosurgical cutting instruments or tools 60 aredescribed herein. A first preferred embodiment of a unipolarelectrosurgical vessel wall cutting tool 160 is depicted in FIGS. 7-10.The unipolar (i.e., single electrode) electrosurgical vessel wallcutting tool 160 has an elongated tool body 164 extending between thearteriotomy tool distal cutting head 162 and a proximal connector pin166 that is suitably long enough to be extended through a port 34 or 36or incision to apply the arteriotomy tool distal cutting head 162 inoperative relation to the selected arteriotomy site. The arteriotomytool distal cutting head 162 comprises a stop ring 170 that provides aframe surrounding an elongated electrosurgical cutting electrode 172that can be applied against the outer surface of a vessel or arterialwall. The stop ring 170 also stops advancement of the elongatedelectrosurgical cutting electrode 172 supported within the frame openinginto the vessel so as to lessen the likelihood that elongatedelectrosurgical cutting electrode 172 would be pressed all the waythrough the vessel lumen and against the opposite side wall of thevessel.

Elongated wire, cutting electrode 172 is supported within the open frameby a pair of electrode support legs 184 and 186 that are electricallyconnected together and to the distal end of a conductor 168 extendingthrough the tool body 164 to the proximal connector pin 166. The stopring 170 is formed with an integral proximal ball 190 (partially shownin FIG. 8) that fits within a socket within socket housing 182. The toolbody 164 comprises an insulating tube 178 that surrounds the conductor168. The connector pin 166 receives and is crimped or welded over aproximal end portion of the conductor 168. A heat shrink outer sleeve(not shown) extends over the socket housing 182 and the tube 178. Thedistal end of the conductor 168 is coupled to the distally extendingends of the elongated electrosurgical cutting electrode 172 by way of acrimp tube extending through the center of the ball of the ball andsocket mechanism.

The elongated electrosurgical cutting electrode 172 extends parallel toand is separated by a distance, e.g. about +/−0.030 inches (1.0 mm) fromthe plane defined by the stop ring 170. In other words, the elongatedelectrosurgical cutting electrode 172 extends parallel to and can bedisposed distally from the plane defined by the stop ring 170 asdepicted for convenience in FIGS. 7-10 or more proximally to the planedefined by the stop ring 170.

The elongated electrosurgical cutting electrode 172 is nominallyoriented at 90° to the axis of the lead body 164. However, in use, theball can be rotated within the socket in a single plane “E” so as toadjust the angle of the elongated electrosurgical cutting electrode 172to the axis of the tool body 164 within a predetermined range so thatthe elongated electrosurgical cutting electrode 172 can be appliedevenly against the vessel wall in axial alignment with the vessel, e.g.,the LAD coronary artery 14 as shown in FIG. 10. The tolerances of theball and socket mechanism can be selected to enable the adjustment to bemade in situ by simply pressing the stop ring 170 and elongatedelectrosurgical cutting electrode 172 against the outer surface of thevessel so as to cause the ball to swivel in the socket.

It will be understood that the ball and socket mechanism can be replacedby a malleable junction of the tool body 164 and the stop ring 170 andthat the entire tool body 164 can be made to be malleable to enablemanual adjustment of the angle of the elongated electrosurgical cuttingelectrode 172 to the axis of the lead body 164.

The elongated electrosurgical cutting electrode 172 can be a 5 mm×5 mmsquare loop of tungsten metal, e.g., the Model LLETZ Loop Electrodeavailable from Valleylab, Inc., of Boulder, Colo. It will be understoodthat the elongated electrosurgical cutting electrode 172 can have an“L-shape” whereby the elongated electrosurgical cutting electrode 172 issupported by only one of the legs 184 or 186.

The tool body 164 and proximal connector pin 166 can be dimensioned tofit into a hand held electrosurgical pen having a hand held switch,e.g., the Model E2100 or E2550 DB from Valleylab, Inc., of Boulder,Colo.

It will be understood that the first preferred embodimentelectrosurgical vessel wall cutting tool 160 depicted in FIGS. 7-10 canbe employed through a small chest incision with or without use of a portin the percutanous procedure depicted in FIG. 5 as well as in any of theother more invasive surgical procedures to access heart 12 describedabove and wherein the heart 12 is either stopped or is beating andstabilized as described further herein.

It will also be understood that a ground pad contacting the patient'sskin can be substituted for the ground wire 50. Or, one or moreelongated electrosurgical cutting electrode and wire ground electrodecan be incorporated into the distal cutting heads 62, 162. Therefore, anumber of bipolar electrosurgical cutting head examples are depicted inFIGS. 11-19. Certain of the bipolar electrosurgical cutting headexamples employ two physically displaced ground electrodes that areelectrically connected in common. It will be understood the cutting andwire ground electrodes are spatially separated, usually in axial orparallel alignment, so that they do not come into direct contact butdeliver the RF energy through the tissue to be cut in the mannerdescribed above. It will also be understood that the designation“elongated electrosurgical cutting electrode” and “wire groundelectrode” in the bipolar embodiments is arbitrary and can be reversedin each case.

The tool body in each bipolar electrosurgical vessel wall cutting toolsupports a ground conductor extending between the longitudinallyextending wire ground electrode(s) and a proximal ground connectorelement as well as an active conductor extending between thelongitudinally extending cutting electrode(s) and a proximal activeconnector element. The ground and active conductors can be supported inparallel or coaxial alignment and electrically insulated from oneanother within the tool body. A bifurcated or in-line proximal connectorassembly can be employed to support the active and ground connectorelements.

A bipolar electrosurgical vessel wall cutting tool 200 is depicted inFIGS. 11 and 12 that is similar to the unipolar electrosurgical vesselwall cutting tool 160 depicted in FIGS. 7-10. The arteriotomy tooldistal cutting head 202 comprises an elongated electrosurgical cuttingelectrode 212 and wire ground electrode 214 supported within andextending from the distal stop ring 210. The active elongatedelectrosurgical cutting electrode 212 is electrically connected to anactive conductor extending through the tool body 204 to the proximalconnector pin 208. The wire ground electrode 214 is configured to besimilar to the active elongated electrosurgical cutting electrode 212but is electrically connected to a ground conductor extending throughthe tool body 204 to the more distal connector ring 206.

The elongated electrosurgical cutting electrode 212 and wire groundelectrode 214 are shown in FIGS. 11 and 12 as square loops similar tocutting electrode 172 and support legs 184 and 186, but mounted todistal stop ring 210 to extend outward such that the support legsdiverge apart. It will be understood that one of the support legs ofeach of the elongated electrosurgical cutting electrode 212 and wireground electrode 214 can be eliminated.

For convenience of illustration, the elongated electrosurgical cuttingelectrode 212 and wire ground electrode 214 are depicted extendingoutward from or distal to the plane of stop ring 210 in FIGS. 11 and 12.It will be understood that the elongated electrosurgical cuttingelectrode 212 and wire ground electrode 214 can be disposed within thestop ring 210 so as to be disposed in a plane or planes proximal to theplane of stop ring 210 in FIGS. 11 and 12.

The arteriotomy tool distal cutting head 202 can be coupled to the toolbody 204 by the above-described ball and socket mechanism or can befixedly attached to the tool body 204. The ball and socket mechanism andthe stop ring 210 are eliminated in the latter case.

Various embodiments of a bipolar electrosurgical vessel wall cuttingtool 240 that are similar to the bipolar electrosurgical vessel wallcutting tool 200 are depicted in FIGS. 13-15 and variants are depictedin FIGS. 16 and 17. The arteriotomy tool distal cutting head 242comprises an elongated electrosurgical cutting electrode 252 and twowire ground electrodes 254 and 256 supported within and extending eitherwithin or outward from the distal stop ring 250.

The active elongated electrosurgical cutting electrode 252 iselectrically connected to an active conductor 270 extending through thetool body 244 to the proximal connector pin 248. The wire groundelectrodes 254 and 256 are configured to be similar to the activeelongated electrosurgical cutting electrode 252 but are electricallyconnected together and to the distal end of a ground conductor 266 thatextends through the tool body 244 to the connector ring 246. Theconductors 266 and 270 are illustrated as co-axially arranged withininsulating 264 and 268 sheaths within the outer sheath 260 of tool body244 but can be in side-by-side arrangement in separate lumens of tube264.

The elongated electrosurgical cutting electrode 252 and wire groundelectrodes 254 and 256 extend parallel to one another and from the planedefined by the stop ring 250 by a distance, e.g. +/−1.0 mm. Theelongated electrosurgical cutting electrode 252 and wire groundelectrodes 254 and 256 can be in the same plane as depicted in FIG. 15or the elongated electrosurgical cutting electrode 252 can be in adifferent plane that the wire ground electrodes 254 and 256. In a firstvariation depicted in FIG. 16, the elongated electrosurgical cuttingelectrode 252′ extends further outward from the wire ground electrodes254 and 256, so that the vessel wall (depicted schematically by thebroken line VW is depressed inward more by the elongated electrosurgicalcutting electrode 252′ than the wire ground electrodes 254 and 256. In asecond variation depicted in FIG. 17, the wire ground electrodes 254′and 256′ extend further outward from the elongated electrosurgicalcutting electrode 252, so that the vessel wall (depicted schematicallyby the broken line VW is depressed inward more by the wire groundelectrodes 254′ and 256′ than the elongated electrosurgical cuttingelectrode 252.

The arteriotomy tool distal cutting head 242 can be coupled to the toolbody 244 by the above-described ball and socket mechanism or can befixedly attached to the tool body 244. The fabrication and uses of thebipolar electrosurgical vessel wall cutting tool 240 are similar tothose described above with respect to the unipolar electrosurgicalvessel wall cutting tool 160.

The elongated electrosurgical cutting electrode 252, 252′ and wireground electrodes 254, ′254 and 256, ′256 are depicted in FIGS. 13-17 assquare loops similar to cutting electrode 172 and support legs 184 and186, but mounted to distal stop ring 210 to extend such that the supportlegs of the wire ground electrodes 254, ′254 and 256, ′256 divergeapart. It will be understood that one of the support legs of each of theelongated electrosurgical cutting electrode 252, 252′ and wire groundelectrodes 254, ′254 and 256, ′256 can be eliminated.

For convenience of illustration, the elongated electrosurgical cuttingelectrode 252, 252′ and wire ground electrodes 254, ′254 and 256, ′256are depicted extending outward from or distal to the plane of stop ring210 in FIGS. 13-17. It will be understood that the elongatedelectrosurgical cutting electrode 252, 252′ and wire ground electrodes254, ′254 and 256, ′256 can be disposed within the stop ring 210 so asto be disposed in a plane or planes proximal to the plane of stop ring210 in FIGS. 13-17.

A further bipolar electrosurgical vessel wall cutting tool 300 isdepicted in FIGS. 18 and 19 and a variant of the electrode configurationis depicted in FIG. 20. In this embodiment, the elongated wire, cuttingand ground electrodes 312 and 314 are suspended substantially parallelto one another and in a plane that is not transverse to the tool axisbut is substantially aligned with the tool axis. The outermost one ofthe elongated wire, cutting and ground electrodes 312 and 314 has asharpened free end 318 that is adapted to be inserted through the vesselwall VW into the vessel lumen. The other of the wire, cutting and groundelectrodes 312, 314 is applied against the outer wall of the bloodvessel so that the RF energy applied between the wire, cutting andground electrodes 312, 314, cuts through the vessel wall VW. The wire,cutting and ground electrodes 312, 314 can be pushed through the vesselwall VW or pulled out through the VW as the RF energy is applied asshown by the arrows in FIGS. 19 and 20.

Thus, FIG. 18 depicts the electrosurgical vessel wall cutting tool 300in use in making an arteriotomy of the LAD coronary artery 14 downstreamfrom the obstruction 38, and FIGS. 19 and 20 depict alternateconfigurations of the elongated wire, cutting and ground electrodes 312,314 extending in parallel from the plane of the stop ring 310. Forconvenience the cutting electrode is designated as the outermostsupported wire electrode having the sharpened tip 318 adapted topenetrate the arterial wall of the LAD coronary artery 14 in the exampleof use depicted in FIG. 18. Alternatively or in addition to thesharpened tip, RF energy may be used to pass electrode 312 through thevessel wall.

The elongated electrosurgical cutting electrode 312 is electricallyconnected to an active conductor extending through the tool body 304 tothe proximal connector pin 308. The wire ground electrode 314 isconfigured to be similar to the active elongated electrosurgical cuttingelectrode 312 but is electrically connected to a ground conductorextending through the tool body 304 to the more distal connector ring306. The elongated electrosurgical cutting electrode 312 and wire groundelectrode 314 extend parallel to and are separated apart by a distancethat approximates the average vessel wall VW thickness and from theplane defined by the stop ring 310 by a distance, e.g. 1.0 mm.

Alternatively, electrosurgical vessel wall cutting tool 300 may beconfigured as a monopolar device (not shown) comprising the elongatedcutting electrode 312. In this embodiment, RF energy is applied throughthe elongated cutting electrode 312 and to a remote grounding pad. Theelongated cutting electrode 312 may have a sharpened free end 318 thatis adapted to be inserted through the vessel wall VW into the vessellumen and/or RF energy may be used to help pass electrode 312 throughthe vessel wall. Once the cutting electrode 312 is within the vessellumen, electrode 312 is pulled out through the VW while RF energy isapplied, thereby forming the arteriotomy.

A still further unipolar electrosurgical vessel wall cutting tool 340 isdepicted in FIGS. 21-23 and comprises an outer sleeve 350 and a toolbody 344 fitted within the outer sleeve lumen 351. The outer sleeve 350extends between a distal sleeve end 356 and a proximal sleeve knob 358.The tool body 344 supports an elongated electrosurgical cuttingelectrode 360 extending away from the tool body distal end 346. Thecutting electrode 360 is electrically connected to the distal end of anactive conductor 366 extending through the tool body 344 to a proximalconnector pin 348. A pair of grasping pincers 352 and 354 are supportedby pincer legs 364 and 366, respectively, that extend through tool bodydistal end 345 and into the tool body 344. The pincer legs 362 and 364have a preformed shape that extends the elongated grasping pincers 352and 354 to extend substantially parallel to one another and to theelongated electrosurgical cutting electrode 360.

The elongated grasping pincers 352 and 354 are thus suspendedsubstantially parallel to one another and in a plane that issubstantially transverse to the tool axis. The distance between theelongated grasping pincers 352 and 354 can be drawn together from thedistance depicted in FIG. 22 to the distance depicted in FIG. 23 byadvancing the sleeve 350 over the pincer legs 362 and 364. The graspingpincers 352 can therefore be used to engage and compress a portion ofthe vessel wall VW together as depicted in FIG. 23.

Thus, FIG. 21 depicts the electrosurgical vessel wall cutting tool 340in use in making an arteriotomy of the LAD coronary artery 14 downstreamfrom the obstruction 38, and FIGS. 22 and 23 depict how the distancebetween the elongated grasping pincers 352 and 354 can be adjusted byremote manipulation of the cutting tool 340. In one preferred procedure,the electrosurgical vessel wall cutting tool 340 is advanced in theconfiguration shown in FIG. 22 through a port or incision to press theelongated electrosurgical cutting electrode 360 in axial alignment withthe vessel axis and against the outer surface of the vessel wall VW ofthe vessel, e.g., LAD coronary artery 14 at the arteriotomy site.

The sleeve 350 and tool body 344 are then manipulated into theconfiguration shown in FIG. 23 to draw the pincer legs 362 and 364 intothe sleeve lumen 351 and compress a portion of the vessel wall VWbetween the elongated wire grasping pincers 352 and 354. The elongatedelectrosurgical cutting electrode 360 makes intimate contact with thevessel wall squeezed together by the elongated grasping pincers 352 and354. Then, RF energy is applied through an elongated electrosurgicalcutting electrode 360 and to a remote grounding pad or a wire groundelectrode, e.g., ground wire electrode 52 depicted in FIG. 10, disposedwithin the lumen of the vessel, e.g., LAD coronary artery 14.Alternatively, grasping pincers 352 and/or 354 may be groundingelectrodes.

Stabilization:

All of the above-described electrosurgical vessel wall cutting tools 60,160, 200, 240, 300, and 340, and equivalents thereto, can be employed inCABG procedures that are conducted while the heart is either arrested orbeating. It may be preferable to employ further heart stabilizationtools and techniques to stabilize the heart around the site of thearteriotomy 15 in LAD coronary artery 14 and to minimize blood lossthrough the arteriotomy. To this end, any of the instruments andtechniques for applying pressure against the epicardial surface can beemployed, e.g., the instruments mounted to the retractors maintainingthe chest wall incision and the techniques disclosed in theabove-referenced '782 patent. Or, a frame of the type described in theabove-referenced '069 patent can be temporarily sutured to or heldagainst the epicardium to immobilize the area and compress the arterylumen.

Alternatively, suction can be applied to the epicardial surface as shownfor example in the above-referenced '295 patent or in commonly assignedU.S. Pat. No. 6,394,948 and PCT Publication WO 02/28287 wherein theinstruments and suction elements are mounted to the surgical table oranother stable platform. The Octopus® flexible tissue stabilizationsystem sold by assignee of the present application can be employed togrip and stabilize or immobilize the epicardial surface tissue on eitherside of the site of a vessel wall where an elongated slit is to be made.

Thus, the use of such a tissue stabilization system 400 to stabilize orimmobilize the epicardial surface tissue on either side of the site ofthe arteriotomy 15 in LAD coronary artery 14 is illustratedschematically in FIG. 24. An articulating or flexible arm 404, 406, isattached to a fixed reference 402, which can be a retractor affixed toan opening in the patient's chest wall or other operating roomequipment, e.g., an operating table. A vacuum source is coupled to alumen of the arm 406 or to flexible tubing (not shown) that in eithercase extends into the interior manifolds of stabilizer suction pads 410and 414 that extend on either side of the site of the arteriotomy 15. Inthis example, the stabilizer suction pads 410 and 414 are formed asdescribed in the above-referenced PCT Publication WO 02/28287, forexample. A plurality of suction ports 412 and 416 extend throughsurfaces of the suction pads 410 and 414, respectively that are appliedagainst the epicardial surface from manifolds within the suction pads410 and 414. In this illustrated embodiment, the manifolds within thesuction pads 410 and 414 are coupled through an air passage within joint408 to a suction tube or lumen of the arm 406 that extends to a vacuumport (not shown). Instead, flexible tubing could be employed as in theOctopus® flexible tissue stabilization system to apply suction from thevacuum source directly into each of the manifolds within the suctionpads 410 and 414. It will be understood that a single horseshoe shapedor rectilinear suction pad could be substituted for the pair ofstabilizer suction pads 410 and 414.

In use, the stabilizer suction pads 410 and 414 are lined up with theaxis of the LAD coronary artery 14 (or other target vessel). The vacuumsource creates suction between the epicardium and the suction pads 410and 414 to minimize heart movement in the area around the site of thearteriotomy. The stabilizer suction pads 410 and 414 can be spread apartin the manner of the Octopus® flexible tissue stabilization system tofurther immobilize the tissue area around the site of the arteriotomy15.

The ground electrode and elongated electrosurgical cutting electrode ofthe above-described electrosurgical vessel wall cutting tools 60, 160,200, 240, 300, and 340, and equivalents thereto can be applied to thesite. RF energy is then applied between the elongated electrosurgicalcutting electrode and the ground electrode in the interval between heartcontractions.

It is also contemplated that the above-described electrosurgical toolsincorporate immobilization devices, e.g., pressure applying feetalongside or frames surrounding the arteriotomy tool distal cuttinghead. Any of the above-described electrosurgical tools 60 can bemodified to incorporate such pressure applying feet or frames.

For example, FIG. 25 depicts a bipolar or unipolar electrosurgicalvessel wall cutting tool 440 in use in making an arteriotomy of the LADcoronary artery 14 having an elongated electrosurgical cutting electrode442 of any of the above described types with or without a ball andsocket mechanism and stop ring. Stabilizer feet 452 and 454 are coupledto the tool body 444 at junction 446. A unipolar electrosurgical vesselwall cutting tool 440 that is adapted to be employed with a remoteground pad on the patient's skin or a ground wire 50 introduced into thevessel lumen such that the ground or return electrode 52 is located inproximity to the cutting electrode as described above with respect toFIG. 6 is illustrated for convenience of description.

The electrosurgical vessel wall cutting tool 440 comprises a tool body444 extending from an elongated electrosurgical cutting electrode 442 atthe tool body distal end to a coupling tool connector element 448adapted to be coupled to a source of RF energy at the tool body proximalend. The electrosurgical cutting electrode 442 is supported to extendoutward or distally and substantially transversely to the axis of thetool body 444. An electrical conductor extends through a conductor lumenof the tool body 444 between the elongated electrosurgical cuttingelectrode 442 and connector element 448.

For example, the electrosurgical vessel wall cutting tool 440 can beintroduced into the chest cavity in any of the above-described surgicalaccess procedures so that the elongated electrosurgical cuttingelectrode 442 is aligned with the axis of and centered over exposedvessel wall of the LAD coronary artery 14 at the site where anarteriotomy is to be made and stabilizer feet 452 and 454 are brought tobear against the epicardium. The surgeon applies pressure through thetool body 444 to press the stabilizer feet 452 and 454 against theepicardium and to press the elongated electrosurgical cutting electrode442 against the vessel wall. Heart movement is minimized in the areaaround the site of the arteriotomy by the applied pressure, and RFenergy is applied to the elongated electrosurgical cutting electrode 442in the interval between heart contractions.

FIG. 26 depicts another example of a bipolar or unipolar electrosurgicalvessel wall cutting tool 460 in use in making an arteriotomy of the LADcoronary artery 14 having an elongated electrosurgical cutting electrode462 of any of the above described types with or without a ball andsocket mechanism and stop ring. A unipolar electrosurgical vessel wallcutting tool 460 that is adapted to be employed with a remote ground padon the patient's skin or a ground wire 50 introduced into the vessellumen such that the ground or return electrode 52 is located inproximity to the cutting electrode as described above with respect toFIG. 6 is illustrated for convenience of description.

The electrosurgical vessel wall cutting tool 460 comprises a tool body464 extending from an elongated electrosurgical cutting electrode 462 atthe tool body distal end to a coupling tool connector element 476adapted to be coupled to a source of RF energy and a vacuum port 478adapted to be coupled with a vacuum source at the tool body proximalend. The electrosurgical cutting electrode 462 is supported to extendoutward or distally and substantially transversely to the axis of thetool body 464. An electrical conductor extends through a conductor lumenof the tool body 464 between the elongated electrosurgical cuttingelectrode 462 and connector element 476.

Stabilizer suction pads 472 and 474 are coupled to the tool body 464 atmanifold 466 to extend on either side of the elongated electrosurgicalcutting electrode 462. In this example, the stabilizer suction pads 472and 474 are formed as described in the above-referenced PCT PublicationWO 02/28287, for example. A plurality of suction ports 470 extendthrough surfaces of the suction pads 472 and 474 that are appliedagainst the epicardial surface from a manifold or plenum within thesuction pads 472 and 474 that is in turn coupled through air passageswithin manifold 466 to a suction tube or lumen 468 of the tool body 464that extends to the vacuum port 478.

In use, the stabilizer suction pads 472 and 474 and elongatedelectrosurgical cutting electrode 462 are lined up with the axis of theLAD coronary artery 14 (or other target vessel). The vacuum sourcecreates suction between the epicardium and the suction pads 472 and 474to minimize heart movement in the area around the site of thearteriotomy. RF energy is applied to the elongated electrosurgicalcutting electrode 462 in the interval between heart contractions.

It will be understood that a single horseshoe shaped or rectilinearsuction pad could be substituted for the pair of stabilizer suction pads472 and 474.

It is also desirable to both stabilize the area of the heart about thearteriotomy site and to occlude the target vessel lumen upstream anddownstream of the arteriotomy site. A further bipolar or unipolarelectrosurgical vessel wall cutting tool 480 that combines an elongatedelectrosurgical cutting electrode 482 of any of the above describedtypes with or without a ball and socket mechanism and stop ring with astabilization and vessel occlusion frame 490 is depicted in FIG. 27 inuse in making an arteriotomy of the LAD coronary artery 14. A unipolarelectrosurgical vessel wall cutting tool 480 that is adapted to beemployed with a remote ground pad on the patient's skin or a ground wire50 introduced into the vessel lumen such that the ground or returnelectrode 52 is located in proximity to the cutting electrode asdescribed above with respect to FIG. 6 is illustrated for convenience ofdescription.

The electrosurgical vessel wall cutting tool 480 comprises a tool body484 extending from an elongated electrosurgical cutting electrode 482 atthe tool body distal end to a coupling tool connector element 488adapted to be coupled to a source of RF energy at the tool body proximalend. The electrosurgical cutting electrode 482 is supported to extendoutward or distally and substantially transversely to the axis of thetool body 484. An electrical conductor extends through a conductor lumenof the tool body 484 between the elongated electrosurgical cuttingelectrode 482 and connector element 488.

In this embodiment, the electrosurgical cutting electrode 482 attachedto tool body 484 is surrounded by a stop ring 486. Frame struts 492 and494 extend from a coupling ring about the tool body 484 to a rectilinearstabilization and vessel occlusion frame 490. Occlusion pads 496 and 498extend distally from the frame 490.

In use, the elongated electrosurgical cutting electrode 482 is alignedwith the axis of the LAD coronary artery 14 (or other target vessel),and the occlusion pads are positioned over the LAD coronary artery. Thesurgeon applies pressure through the tool body 484 to press frame 490against the epicardium and to press the elongated electrosurgicalcutting electrode 482 against the vessel wall and stop ring 486 againstthe epicardium. The occlusion pads 496 and 498 extend further than theframe 490 into the vessel walls to occlude the LAD coronary artery 14.Heart movement is thereby minimized in the area around the site of thearteriotomy by the applied pressure, and RF energy is applied to theelongated electrosurgical cutting electrode 482 in the interval betweenheart contractions.

It will be understood that the features of the electrosurgical tools 460and 480 can be combined by forming the pair of stabilizer suction pads472 and 474 in the shape of the rectilinear frame 490 having theocclusion pads 496 and 498 extending distally from the frame 490.

A still further embodiment of a bipolar or unipolar electrosurgicalvessel wall cutting tool 500 is depicted in FIGS. 28-32, wherein suctionis applied through an arcuate suction pad and lumen of the tool body todraw the vessel wall against the elongated electrosurgical cuttingelectrode. The suction pad is configured to facilitate the axialalignment of the elongated electrosurgical cutting electrode with thevessel axis and the centering of the elongated electrosurgical cuttingelectrode over the exposed vessel wall. A unipolar electrosurgicalvessel wall cutting tool 500 that is adapted to be employed with aremote ground pad on the patient's skin or a ground wire 50 introducedinto the vessel lumen such that the ground or return electrode 52 islocated in proximity to the cutting electrode as described above withrespect to FIG. 6 is illustrated for convenience of description.

Thus, the electrosurgical vessel wall cutting tool 500 comprises a toolbody 502 extending from a suction pad 504 and elongated electrosurgicalcutting electrode 510 at the tool body distal end to a coupling toolconnector element 506 and a vacuum port 508 adapted to be coupled with avacuum source at the tool body proximal end. The electrosurgical cuttingelectrode 510 is supported to extend outward or distally from innersurface 512 of suction pad 504 and to extend substantially transverselyto the axis of the tool body 502. An electrical conductor extendsthrough a conductor lumen of the tool body 502 between the elongatedelectrosurgical cutting electrode 510 and connector element 506.

A plurality of suction ports 516 extend through the suction pad innersurface 512 from a manifold or plenum within the arcuate suction pad 504that is in turn coupled to a further suction lumen of the tool body 502that extends to the vacuum port 508. The cutting pad 504 is arcuate incross-section such that the suction pad inner surface 512 can be fittedover and against an exposed arcuate section of vessel wall that issurgically accessed, and suction can be applied through the suctionports 516 to draw the vessel wall against the suction pad inner surface512 and elongated electrosurgical cutting electrode 510. For example,the electrosurgical vessel wall cutting tool 500 can be introduced intothe chest cavity in any of the above-described surgical accessprocedures so that the suction pad inner surface 512 and electrosurgicalcutting electrode 510 are brought into axial alignment with a portion ofa coronary artery, e.g., LAD coronary artery 14, at the site where anarteriotomy is to be made.

The arcuate suction pad 504 has open ends in the embodiments depicted inFIGS. 28-30. However, the ends can closed by end walls 518-520 as shownin the embodiment depicted in FIGS. 31 and 32 to provide the vesselocclusion function of the occlusion pads 496 and 498 of theelectrosurgical tool 480 depicted in FIG. 27 and described above.

In use, the arcuate suction pad 504 and elongated electrosurgicalcutting electrode 510 are aligned with the axis of the LAD coronaryartery 14 (or other target vessel). The vacuum source creates suctionbetween the vessel wall and the suction pad inner surface 512 tominimize vessel movement in the area around the site of the arteriotomy.RF energy is applied to the elongated electrosurgical cutting electrode510 in the interval between heart contractions.

FIGS. 33-35 illustrate the principles of a further embodiment of anelectrosurgical vessel wall cutting tool 600 operating in conjunctionwith a mechanism for delivering a wire ground electrode 610 into thevessel lumen through a needle puncture of the vessel wall. The mechanismfor delivering a wire ground electrode 610 into the vessel lumen can beintegrally incorporated with the tool body 604 as illustrated or can beseparate from the tool body for use in any of the unipolarelectrosurgical vessel wall cutting tools of the present invention. Inthis illustration, an arteriotomy is created in the LAD coronary artery14 by RF energy applied between the elongated electrosurgical cuttingelectrode 602 and a wire ground electrode 610 when the wire groundelectrode 610 is deployed within the artery lumen and the elongatedelectrosurgical cutting electrode 602 is applied to the arterial wall.

The elongated electrosurgical cutting electrode 602 is electricallyconnected to the connector element or pin 606 through a conductorextending through tool body 604. The elongated electrosurgical cuttingelectrode 602 can take any of the forms depicted in the figures.

The wire ground electrode 610 comprises a length of uninsulated orpartially uninsulated, resilient wire 612 that can be extended out fromor drawn into a lumen or pair of lumens 614 and 616 of a needle 620having a vessel wall penetrating needle tip 618. One end of the wire 612is fixed within the lumen 614 and the other free end of the wire 612extends from the proximal end opening of the lumen 616 and is attachedto a further connector element 622. A slot 624 is formed extendingbetween the lumens 614 and 616 in the needle tip 618 as shown in FIG.34. It will be understood that the needle 620 is expanded in relativesize to the elongated electrosurgical cutting electrode 602 in thefigures for ease in illustrating its features. Wire 612 may comprise oneor more of a number of materials including nitinol, stainless, tungstenand titanium. The wire material may or may not be annealed.

In use, the free end of the wire 612 is pulled outward from the proximalend opening of the lumen 616 sufficiently to retract the wire loopthrough the lumen 616 and into slot 624 in the beveled needle tip 618.The beveled needle tip 618 is inserted through the vessel wall, and thefree end of the wire 612 is advanced into the proximal end opening ofthe lumen 616 sufficiently to form and expand the wire loop from slot624 in the beveled needle tip 618 as shown in FIG. 34 until the fullsized wire loop is formed as shown in FIG. 35. The spring tension of thewire loop ensures that the sides of the loop are in intimate contactwith opposite sides of the interior vessel wall. Thus, one side of thewire loop is in intimate contact with the interior vessel wallimmediately across from the outer surface of the vessel wall that theelongated electrosurgical cutting electrode 602 is applied against. TheRF energy generator is coupled with the connector elements 606 and 622,and an arteriotomy having a length equal to the length of the elongatedelectrosurgical cutting electrode 602 is created by application or RFenergy between the elongated electrosurgical cutting electrode 602 andthe wire ground electrode 610.

Automatic Switch

In the above-described embodiments, it may be desirable to incorporate apressure responsive mechanical switch within the tool bodies so that theRF energy can only be applied successfully when the elongatedelectrosurgical cutting electrode is in intimate contact with the vesselwall. Therefore, FIG. 36 schematically illustrate a universalelectrosurgical tool 60′ representing a possible modification of any theabove-described electrosurgical tools having a spring loaded switchmechanism 75 incorporated between the tool body 64′ and an end cap 68that displaces the electrosurgical cutting electrode 62′ from the toolconductor 66. The elongated electrode surgical cutting electrode 62′ isrepresented as a wire loop electrode of the types described above butmay take other forms, e.g., the elongated cutting electrode 510 of theelectrosurgical vessel wall cutting tool 500.

In this embodiment, the tool conductor 66 terminates distally in aswitch pad 70 centrally positioned at the distal end of tool body 64′.The loop ends of the electrosurgical cutting electrode 62′ are joinedtogether and to a switch pad 72 supported by the end cap 68 surroundingtool body 64′. An annular spring retention space is formed between thedistal end of tool body 64′ and the interior of the end cap 68. Either asingle spring or the depicted plurality of springs 74, 76 are positionedand entrapped in the annular recess surrounding the switch pads 70 and72. The end cap 68 and springs 74, 76 are entrapped by flange 78extending inwardly into a groove of tool body 64′ that limits relativedisplacement of the end cap 68 from the tool body 64′.

In use, the elongated electrosurgical cutting electrode 62′ is normallydisconnected from the conductor 66 by the force of the springs 74, 76acting between the end cap 68 and tool body 64′ as depicted in FIG. 36.Thus, RF energy applied that may be conducted through the conductor 66will not be applied to the electrosurgical cutting electrode 62′ if theelectrosurgical cutting electrode 62′ is only lightly in contact with ordisplaced from the vessel wall VW as shown in FIG. 36.

The elongated electrosurgical cutting electrode 62′ is connected withthe conductor 66 when the force of the springs 74, 76 acting between theend cap 68 and tool body 64′ is overcome as depicted in FIG. 37. Thus,RF energy applied that may be conducted through the conductor 66 canthen be applied to the electrosurgical cutting electrode 62′ as long asthe electrosurgical cutting electrode 62′ is firmly in contact with thevessel wall VW as shown in FIG. 37.

It will be understood that the RF energy generator coupled to thegrounding pad or ground electrode 52 of FIG. 6 can be of the type thatmonitors current, voltage, series impedance and temperature and governsthe application of RF energy. Thus, the state of the switch mechanismillustrated in FIGS. 33 and 34 can also be automatically monitored, andthe physician can be provided with an indication that the switch pads70, 72 are open or closed (i.e., in contact) when applying theelectrosurgical cutting electrode 62′ into contact with the vessel wallVW. The physician can then close the hand switch of the tool holder toapply the RF cutting energy when it is indicated that the switch padsare closed.

Source Vessel Arteriotomy for Side-to-Side Anastomosis:

Typically, the excised portion of the left IMA or right IMA, a radialartery or gastroepiploic artery is harvested within a flap of tissuereferred to as a “pedicle” 35 as shown in FIG. 38. The pedicle 35provides a small platform that can be grasped by forceps to position thevessel for making the side wall arteriotomy and during the completion ofthe anastomosis. Many of the above described unipolar, bipolar ormulti-polar electrosurgical vessel wall cutting tools can be employed tomake an arteriotomy in the sidewall of the surgically freed portion ofthe source vessel.

For example, FIG. 38 illustrates the use of the electrosurgical vesselwall cutting tool 500 against the vessel wall of the left IMA 30. Theground electrode 82 of a ground tool or wire 80 can be inserted into thelumen of the left IMA either by a trans-arterial route or through theopen end electrode as depicted in FIG. 35 when a unipolarelectrosurgical vessel wall cutting tool is employed. The wire body 84can be inserted through an open chest or a closed chest, e.g., through aport or a cannula, or through a catheter, and the wire terminal 86 canbe connected with the RF energy generator.

Further bipolar electrosurgical vessel wall cutting tools 540 and 570are schematically depicted in FIGS. 39-42 that can be advantageouslyused to form an arteriotomy in the side wall of a vessel, e.g., theillustrated left IMA 30. The electrosurgical vessel wall cutting tools540 and 570 are configured as forceps having forceps handles coupledtogether by a swivel pin and having active and ground RF electrodesformed on the jaw surfaces that face one another and can be broughttogether or apart by movement of the forceps handles.

The electrosurgical vessel wall cutting tool 540 comprises a firsthandle 542 and a second handle 552 joined together at a swivel pin 562.Handle 542 extends to a first jaw 544 supporting an elongated exposedelectrode 546 that can be used either as an electrosurgical cutting orground electrode. A conductor 548 enclosed within the handle 542 extendsbetween the elongated electrosurgical cutting or ground electrode 546and a connector pin 550 adapted to be attached by a cable to either theactive or ground output terminal of an RF energy generator. Similarly,second handle 552 extends to a second jaw 554 supporting an elongatedelectrosurgical cutting or ground electrode 556. A conductor 558enclosed within the handle 552 extends between the elongatedelectrosurgical cutting or ground electrode 556 and a connector pin 560adapted to be attached by a cable to either the active or ground outputterminal of an RF energy generator.

In use, cables from the RF energy generator output terminals are coupledto the connector pins 550 and 560. First jaw 544, for example, isinserted axially through the open cut end and into the lumen 37 of theleft IMA 30 to present the electrode 546 against the inner surface ofthe vessel wall and the electrode 556 against the outer surface of thevessel wall. The RF energy is applied through the vessel wall betweenthe opposed electrodes 546 and 556 to cut away the vessel wall and formthe arteriotomy, e.g., arteriotomy 33 depicted in FIG. 3. The length ofthe arteriotomy can be either dictated by the lengths of the opposedelectrodes 546 and 556 or made longer by moving the jaws 544, 554 andsuccessively cutting the vessel wall until a desired length is achieved.

The electrosurgical vessel wall cutting tool 570 also comprises a firsthandle 572 and a second handle 582 joined together at a swivel pin 592.First handle 572 extends to a somewhat arcuate first jaw 574 supportingan elongated, exposed, electrosurgical ground electrode 576 that isintended to be applied against the exposed outer surface of the vesselwall on one side of the pedicle 35. A conductor 578 enclosed within thehandle 572 extends between the elongated electrosurgical groundelectrode 576 and a connector pin 580 adapted to be attached by a cableto the ground output terminal of an RF energy generator. Similarly,second handle 582 extends to a somewhat arcuate second jaw 584supporting an elongated electrosurgical cutting electrode 586 adapted tobe applied against the outer surface of the vessel wall on the otherside of the pedicle 35. A conductor 588 enclosed within the handle 582extends between the elongated eletrosurgical cutting electrode 586 and aconnector pin 590 adapted to be attached by a cable to the active outputterminal of an RF energy generator.

In this embodiment, the electrosurgical cutting electrode 586 and thesupporting jaw 584 are elongated in the axial direction of the vesselsuch that the axial length of the electrosurgical cutting electrode 586defines the length of the arteriotomy 33 parallel to the vessel axis.The electrosurgical ground electrode 576 may be the same length andwider than the electrosurgical cutting electrode 586 so that the surfacearea of the electrosurgical ground electrode 576 exceeds surface area ofthe electrosurgical cutting electrode 586 to concentrate current densityat the electrosurgical cutting electrode 586 and reduce current densityat the electrosurgical ground electrode 576.

In use, cables from the RF energy generator output terminals are coupledto the connector pins 580 and 590. Jaws 574 and 584 are applied toeither side of the vessel wall exposed from the pedicle 35. The RFenergy is applied through the vessel wall between the opposed electrodes586 and 576 to cut away the vessel wall and form the arteriotomy, e.g.,arteriotomy 33 depicted in FIG. 3. The RF energy is concentrated alongthe length and width of the elongated electrosurgical cutting electrode586 to cut the arteriotomy 33 only in the vessel wall contacted by theelectrosurgical cutting electrode 586.

Another preferred embodiment of an electrosurgical vessel wall cuttingtool 860 is depicted in FIGS. 43 and 44. The unipolar (i.e., singleelectrode) electrosurgical vessel wall cutting tool 860 has an elongatedconducting tool body 868 extending between the distal cutting head 862and a proximal connector pin 866. Tool body 868 is suitably long enoughto be extended through an incision or port 34 or 36 to apply the distalcutting head 862 in operative relation to the selected arteriotomy site.Tool body 868 is preferably a metal conducting tube.

The distal cutting head 862 comprises a pair of tissue sensingelectrodes 870 and 871 adjacent an elongated electrosurgical cuttingelectrode 872 that can be applied against the outer surface of a vesselor arterial wall. The sensing electrodes 870 and 871 stop advancement ofthe elongated electrosurgical cutting electrode 872 into the vessel aswell as control the output of RF energy so as to lessen the likelihoodthat the elongated electrosurgical cutting electrode 872 would bepressed all the way through the vessel lumen and against the oppositeside wall of the vessel, thereby preventing the overheating of tissuelocated on the opposite side wall of the vessel. Sensing electrodes 870and 871 are coupled to conductors 875 and 876, respectively. During useof device 860, conductors 875 and 876 are coupled to a signal generatingsource (not shown).

The signal generator is capable of producing a sufficiently highfrequency signal to sensing electrodes 870 and 871 so as not to causethe stimulation of cardiac tissue, if so desired. An electricalcharacteristic such as impedance of the series circuit between tissuesensing electrodes 870 and 871 is monitored during application of RFenergy to cutting electrode 872. The sudden change in an electricalcharacteristic such as impedance as the tissue sensing electrodescontact tissue is detected and employed to signal completion and/or toautomatically terminate the RF energy. For example, the RF energy isautomatically cut-off when sensing electrodes 870 and/or 871 come intocontact with tissue. Elongated wire, cutting electrode 872 is supportedat the end of tool body 868 by a pair of electrode support legs 884 and886 that are electrically connected together and to the distal end oftool body 868 extending through an insulating sheath 864 to the proximalconnector pin 866. Insulating sheath 864 comprises an insulatingmaterial that at least partially surrounds the conducting tool body 868.The connector pin 866 receives and is crimped or welded over a proximalend portion of the conducting tool body 868. The distal end of tool body868 is coupled to the distally extending ends of the elongatedelectrosurgical cutting electrode 872 by way of a crimp.

The elongated electrosurgical cutting electrode 872 may be nominallyoriented 90° to the axis of tool body 868. The elongated electrosurgicalcutting electrode 872 can be a 5 mm×5 mm square loop of tungsten metal,e.g., the Model LLETZ Loop Electrode available from Valleylab, Inc., ofBoulder, Colo. It will be understood that the elongated electrosurgicalcutting electrode 872 can have alternative shapes, e.g., a “V-shape” ora “L-shape” whereby the elongated electrosurgical cutting electrode 872is supported by only one of the legs 884 or 886.

Tool body 868 is fixed within lumen 896 of tool member 892 whileconductors 875 and 876 pass through lumens 848 and 849, respectively(see FIG. 45). In addition, tool member 892 has a recessed space or slot897 at its proximal end for receiving the distal end of tool member 890.Tool member 892 and tool member 890 preferably fit together movablywherein the distal end of tool member 890 can slide back and forthwithin the proximal end of tool member 892. The fit between tool members890 and 892 is designed so that members 890 and 892 will not rotaterelative to each other. One method for allowing linear travel but notrotational travel between members 890 and 892 is to use a keyed slotdesign. For example, providing a multi-sided shape, e.g., a hexagon, tothe distal end of member 890 and the corresponding multi-sided shapedslot within the proximal end of member 892 allows linear travel but notrotational travel between the two members. Tool members 890 and 892 arepreferably made of an insulating or non-conducting material.

The distal end of tool member 891 is coupled movably to the proximal endof tool member 892. Tool member 891 is allowed to rotate around theproximal end of tool member 892 but is not allowed to travel linearrelative to tool member 892. The proximal end of tool member 891 isthreaded onto threads 898 (see FIG. 46) of tool member 890. A portion oftool body 868 resides movably within lumen 899 of tool member 890.Rotating tool member 891 around tool member 892 causes tool member 890to travel in a linear fashion relative to tool members 891 and 892 aswell as tool body 868, thereby allowing a physician to selectively movesensing electrodes 870 and 871 relative to cutting electrode 872 viarotation of tool member 891. Sensing electrodes 870 and 871 are bothfixed to tool member 890. An indicator, e.g., a scale 895 on tool member890, may be used to provide information to the physician about thedistance between sensing electrodes 870 and 871 and cutting electrode872, thereby allowing the physician to dial-in the appropriate cutdepth. A variety of indicators may be used to indicate to the physiciana selected cutting depth. For example, an electronic indicator may beused.

A variety of techniques or means may be employed for controlling thecutting depth of device 860. Tissue activated switches for shutting offor modulating RF energy output when a desired cut depth is reached maybe employed. For example, one or more sensors, electrical sensors, fiberoptic sensors, proximity sensors that measure conductance and/ormechanical switches may be used. For example, sensing electrodes 870 and871 of device 860 may be replaced with one or more small mechanicallyactivated switches. When the mechanical switches are pushed againsttissue they become activated thereby shutting off the RF energy beingsupplied to cutting electrode 872. In addition, sensors that canidentify different tissue types may be used to modulate the output of RFenergy. For example, fatty tissue has different impedance than vesselwall tissue. Sensors designed to sense difference in impedance, e.g.,sensing electrodes 870 and 871, may be used to change the RF energyoutput to cutting electrode 872 based on the type of tissue being cut.

It will be understood that the electrosurgical vessel wall cutting tool860 depicted in FIGS. 43 and 44 can be employed through a small chestincision with or without use of a port in the percutanous proceduredepicted in FIG. 5 as well as in any of the other more invasive surgicalprocedures to access heart 12 described above and wherein the heart 12is either stopped or is beating and stabilized as described furtherherein. For example, in one embodiment of the present invention, toolmember 890 and tool body 868 may be suitably long enough to be extendedthrough a small incision or port 34 or 36 to apply the distal cuttinghead 862 in operative relation to the selected arteriotomy site.

It will also be understood that a ground pad contacting the patient'sskin or a ground wire as described above may be used withelectrosurgical vessel wall cutting tool 860. For example, a return orground electrode may be introduced into the lumen of the vessel, e.g.,LAD coronary artery 14, into close proximity with the cutting electrode872 at the distal cutting head 862. RF energy is then applied throughthe elongated electrosurgical cutting electrode and the return or groundelectrode.

CONCLUSION

All patents and publications referenced herein are hereby incorporatedby reference in their entireties.

It will be understood that certain of the above-described structures,functions and operations of the above-described preferred embodimentsare not necessary to practice the present invention and are included inthe description simply for completeness of an exemplary embodiment orembodiments. It will also be understood that there may be otherstructures, functions and operations ancillary to the typical operationof electrosurgical instruments and electrosurgery that are not disclosedand are not necessary to the practice of the present invention.

In addition, it will be understood that specifically describedstructures, functions and operations set forth in the above-referencedpatents can be practiced in conjunction with the present invention, butthey are not essential to its practice.

It is therefore to be understood, that within the scope of the appendedclaims, the invention may be practiced otherwise than as specificallydescribed without actually departing from the spirit and scope of thepresent invention.

1. An electrosurgical vessel wall cutting tool adapted to be employedwith a ground electrode in contact with the body of a patient andcoupled to a source of RF energy for making an elongated slit through avessel wall and into a lumen of a body vessel, having a vessel axis, ofa patient that is surgically accessed in a surgical operating fieldcomprising: an elongated tool body extending between a tool bodyproximal end and a tool body distal end; a connector element supportedby the tool body adapted to be coupled with the source of RF energy; anelongated electrosurgical cutting electrode supported at the tool bodydistal end, the elongated electrosurgical cutting electrode having apredetermined cutting electrode length exceeding the cutting electrodewidth; an electrical conductor within the tool body extending betweenand coupled with the connector element and the elongated electrosurgicalcutting electrode, whereby the elongated tool body is adapted to bemanipulated to align and amply the cutting electrode length of theelongated electrosurgical cutting electrode against a surface of thevessel wall in substantially parallel alignment with the vessel axis soas to apply RF energy between the electrosurgical cutting electrode andthe ground electrode at an energy level and for a duration sufficient tocut an elongated slit through the vessel wall where the elongatedelectrosurgical cutting electrode is applied to the surface of thevessel wall, wherein the ground electrode is supported by the tool bodyand adapted to penetrate through the vessel wall and into the lumen ofthe body vessel in proximity with the elongated electrosurgical cuttingelectrode applied to an outer surface of the vessel wall.
 2. Theelectrosurgical vessel wall cutting tool of claim 1, wherein the groundelectrode comprises an elongated wire extending to a wire tip adapted tobe advanced through the vessel wall to dispose the ground electrodewithin the lumen of the body vessel.
 3. The electrosurgical vessel wallcutting tool of claim 1, further comprising: a further connector elementsupported by the tool body; and a further electrical conductor withinthe tool body extending between and coupled with the further connectorelement and the ground electrode, and wherein: the ground electrode iscoupled with the further electrical conductor and supported at the toolbody distal end to extend into contact with an outer surface of thevessel wall substantially in parallel alignment with the elongatedelectrosurgical cutting electrode, whereby the ground electrode and theelongated electrosurgical cutting electrode are adapted to be applied tothe outer surface of the vessel wall.
 4. The electrosurgical vessel wallcutting tool of claim 1, further comprising: a further connector elementsupported by the tool body; and a further electrical conductor withinthe tool body extending between and coupled with the further connectorelement and the ground electrode, and wherein: the ground electrodecomprises first and second elongated ground electrodes coupled with thefurther electrical conductor and supported at the tool body distal endto dispose the first elongated ground electrode substantially inparallel with and along a first side of the elongated electrosurgicalcutting electrode and the second elongated ground electrodesubstantially in parallel with and along a second side of the elongatedelectrosurgical cutting electrode.
 5. The electrosurgical vessel wallcutting tool of claim 4, wherein: the first and second elongated groundelectrodes are supported at the tool body distal end to dispose thefirst and second elongated ground electrodes in a common plane; and theelongated electrosurgical cutting electrode is disposed substantially inthe common plane with the first and second elongated ground electrodes.6. The electrosurgical vessel wall cutting tool of claim 4, wherein: thefirst and second elongated ground electrodes are supported at the toolbody distal end to dispose the first and second elongated groundelectrodes in a common plane; and the elongated electrosurgical cuttingelectrode is disposed substantially outside the common plane with thefirst and second elongated ground electrodes.
 7. The electrosurgicalvessel wall cutting tool of claim 4, wherein: the first and secondelongated ground electrodes are supported at the tool body distal end todispose the first and second elongated ground electrodes in a commonplane at a first distance from the tool body distal end; and theelongated electrosurgical cutting electrode is disposed substantiallyoutside the common plane with the first and second elongated groundelectrodes at a second distance greater than the first distance.
 8. Theelectrosurgical vessel wall cutting tool of claim 4, wherein: the firstand second elongated ground electrodes are supported at the tool bodydistal end to dispose the first and second elongated ground electrodesin a common plane at a first distance from the tool body distal end; andthe elongated electrosurgical cutting electrode is disposedsubstantially outside the common plane with the first and secondelongated ground electrodes at a second distance less than the firstdistance.
 9. The electrosurgical vessel wall cutting tool of claim 1,further comprising: a further connector element supported by the toolbody; and a further electrical conductor within the tool body extendingbetween and coupled with the further connector element and the groundelectrode, and wherein: the ground electrode comprises first and secondground electrodes coupled with the further electrical conductor andsupported at the tool body distal end to dispose the first and secondground electrodes at a first distance from the tool body distal end; andthe elongated electrosurgical cutting electrode is disposed at a seconddistance from the tool body distal end, the second distance exceedingthe first distance.
 10. The electrosurgical vessel wall cutting tool ofclaim 1, further comprising: a further connector element supported bythe tool body; and a further electrical conductor within the tool bodyextending between and coupled with the further connector element and theground electrode, and wherein: the ground electrode comprises first andsecond ground electrodes coupled with the further electrical conductorand supported at the tool body distal end to dispose the first andsecond ground electrodes at a first distance from the tool body distalend; and the elongated electrosurgical cutting electrode is disposed ata second distance from the tool body distal end, the first distanceexceeding the second distance.
 11. The electrosurgical vessel wallcutting tool of claim 1, further comprising means for applying suctionto the body vessel to stabilize the body vessel from movement and tomaintain the elongated electrosurgical cutting electrode in contact withthe surface of the body vessel.
 12. The electrosurgical vessel wallcutting tool of claim 1, further comprising: a further connector elementsupported by the tool body; and a further electrical conductor withinthe tool body extending between and coupled with the further connectorelement and the ground electrode, and wherein: the ground electrodecomprises first and second ground electrodes coupled with the furtherelectrical conductor and supported at the tool body distal end todispose the first and second ground electrodes at a predetermineddistance from the tool body distal end; and the elongatedelectrosurgical cutting electrode is disposed at the predetermineddistance from the tool body distal end.
 13. The electrosurgical vesselwall cutting tool of claim 1, wherein the ground electrode is adapted tobe introduced into the vessel lumen and disposed in proximity to theelongated electrosurgical cutting electrode applied against an outersurface of the vessel wall through the use of a ground wire deploymentdevice comprising: a needle comprising a needle body extending between adistal needle tip adapted to penetrate the vessel wall from the outersurface of the vessel wall and a proximal needle body end, and a needlelumen extending between a needle tip lumen opening and a proximal needlelumen opening disposed between and a needle tip; a ground wire disposedwithin the needle lumen and extending from the proximal needle lumen endopening to a ground wire connector element adapted to be coupled to theRF energy generator, the ground wire adapted to be advanced out of theneedle tip lumen opening through the vessel wall to form a wire loopwithin the vessel lumen to apply at least a section of the wire loopagainst the interior surface of the vessel wall in proximity with theelongated electrosurgical cutting electrode applied to the outer surfaceof the vessel wall.
 14. The electrosurgical vessel wall cutting tool ofclaim 13, wherein the needle is integrally attached to the tool body.15. The electrosurgical vessel wall cutting tool of claim 1, wherein thebody vessel is supported by body tissue and further comprising means forapplying suction to the body tissue alongside the body vessel tostabilize the body vessel from movement and to maintain the elongatedelectrosurgical cutting electrode in contact with the surface of thebody vessel.
 16. The electrosurgical vessel wall cutting tool of claim1, wherein the body vessel is supported by body tissue and furthercomprising means for applying force against the body tissue alongsidethe body vessel to stabilize the body vessel from movement and tomaintain the elongated electrosurgical cutting electrode in contact withthe surface of the body vessel.
 17. The electrosurgical vessel wallcutting tool of claim 1, wherein the body vessel is a blood vesselsupported by body tissue containing blood and further comprising anocclusion frame adapted to be applied against the blood vessel and bodytissue to compress the blood vessel lumen and inhibit blood loss throughthe elongated slit.
 18. The electrosurgical vessel wall cutting tool ofclaim 1, wherein the body vessel is supported by body tissue, a sectionof the body vessel is surgically dissected from the body tissue, and anopening is made through the vessel wall, and wherein: the tool bodyfurther comprises a forceps having first and second opposable jawscoupled to first and second handles, respectively, the forcepssupporting the ground electrode on the first jaw and the elongatedelectrosurgical cutting electrode on the second jaw, whereby the firstjaw is adapted to be inserted through the vessel wall opening into thevessel lumen to apply the ground electrode in contact with an interiorsurface of the vessel wall and the second jaw is adapted to be broughtto bear against an outer surface of the vessel wall to apply theelongated electrosurgical cutting electrode in contact with the outersurface of the vessel wall as the first and second opposable jaws arebrought together by manipulation of the first and second handles. 19.The electrosurgical vessel wall cutting tool of claim 1, wherein thebody vessel is supported by body tissue, a section of the body vessel issurgically dissected from the body tissue, and an opening is madethrough the vessel wall, and wherein: the tool body further comprises aforceps having first and second opposable jaws coupled to first andsecond handles, respectively, the forceps supporting the elongatedelectrosurgical cutting electrode on the first jaw and the groundelectrode on the second jaw, whereby the first jaw is adapted to beinserted through the vessel wall opening into the vessel lumen to applythe elongated electrosurgical cutting electrode in contact with aninterior surface of the vessel wall and the second jaw is adapted to bebrought to bear against an outer surface of the vessel wall to apply theground electrode in contact with the outer surface of the vessel wall asthe first and second opposable jaws are brought together by manipulationof the first and second handles.